On the Microtopography of Upland Bogs in the Daisetsuzan Mountains, Hokkaido

Abstract

This study aims to clarify the genesis of bank (Kermi) and hollow (Schlenke) complexes in upland bogs. The author investigated the microtopography and the superficial deposits of two upland bogs, the Koganegahara bog and the bog situated on the eastern slope of Ponchubetsudake, in the Daisetsuzan Mountains. The results are summarized as follows:1) In the study areas the formation of periglacial slopes with solifluction lobes is inferred to have preceded the appearance of upland bogs. The microrelief of solifiuction lobes must have provided preferable condition to peat accumulation and bank and hollow complexes development. Previous studies of the paleoenvironment and the peat accumulation rate in the Daisetsuzan Mountains suggest that solifluction lobes were formed in the age around 4, 000-3, 000y. B. P.2) Some of bank and hollow complexes originate in the microrelief caused by slide-type mass movement of peat layer itself. Tephra layers intercalated in the peat layer indicate that the mass movement occurred at the time after about 200y. B. P.